Final answer:
A patient's claim of being possessed by a dead relative reflects delusional thinking, more precisely, a delusion of possession. The correct answer is option d.
Step-by-step explanation:
A patient stating, "I am possessed by my dead father," is describing a belief characteristic of a delusion. This kind of thought content is not associated with a hallucination, which involves sensory perceptions without a stimulus, nor with loose association or tangential speech, which relate to the structure of thought and speech, respectively.
The correct answer to what type of thought content this represents is a delusion, and specifically, it could be categorized as a delusion of possession, which is a belief that one's thoughts, feelings, or actions are not one's own, but rather those of someone or something else.
It is not necessarily a grandiose delusion—typically characterized by an inflated sense of self-importance or power—unless the belief about possession entails some form of grandiosity.